Line messages were sent to a friend from the mobile phone of Natsumi Hirata, a 13-year-old girl who was found slain in Takatsuki, Osaka Prefecture, on Aug. 13, saying she would go to Kyoto and probably wouldn't be coming back, it was learned Friday.

Police investigators are trying to determine if Hirata actually sent the messages.

According to sources close to Hirata's friend, the friend received the last message at around 4 or 5 p.m. on Aug. 13, a few hours before Hirata was believed to have died.

Investigators also found that Hirata's socks and clothes weren't dirty, leading them to believe that she was killed indoors or in a car. Hirata wasn't wearing any shoes when her body was found.

Hirata, a first-year junior high school student from Neyagawa, Osaka, was found dead at around 11 p.m. in a parking lot of a distribution firm. Security camera footage showed Hirata and her classmate, Ryoto Hoshino, 12, who remains missing, wandering near Keihan Neyagawashi Station in the early morning of the same day.

Investigators said a Line message was also sent at around 6:30 a.m., saying Hirata would go to Kyoto with Hoshino and that she did not intend to return home to Neyagawa or contact her family.

They said Hirata had been sending messages to her friends frequently after she left home on Aug. 12, but her mobile phone has not been found.